Thermostatically controlled unit



Feb. 17, 1942.

"J. E WOODS I THERMOSTATICALLY bomnogggngmi'r Filed Jan. '30, 1940 Patented Feb. 17, 1942 THERMOSTATICALLY CONTROLLED UNIT John E. Woods, Brookline, Mass, assignor to Clifford Manufacturing 00., Boston, corporation of Delaware Mass, a

Application January 30, 1940, Serial No. 316,406

1 Claim. (Cl

The present invention relates to improvements in thermostatic units of the general type employing a diaphragm or bellows hermetically sealed to a length of capillary tubing which reflects the temperature at a remote point,'causing the free end of the bellows unit to operate a switch or valve in a manner which will be obvious to those skilled in the art.

The purpose of the invention is to reorganize and improve such a unit in a manner to best adapt it for commercial production and improve its economy of manufacture, while at the same time substantially strengthening and improving the bond between the capillary and the expansible unit.

For the attainment of the above and other objects, the various features of the invention consist in certain novel features of construction, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in. the art from the following description.

The accompanying drawing illustrates a longitudinal section upon an enlarged, scale of a unit satisfactorily embodying the features of the invention, and useful for a variety of purposes.

Units such a those shown in the illustrated embodiment of the invention are commonly employed for the remote control of refrigerating mechanism and the like, these units comprising a bellows or diaphragm with a suitable length of capillary tubing sealed thereto. The interior space within the bellows and capillary is fllled with thermostatic fluid which expands and contracts under the influence of temperature. The capillaryat its end removed from the bellows is placed within the space to be controlled, which may be the interior of the refrigerator, and leads therefrom to the bellows which is assembled with the control mechanism. Commonly this mechanism is in the form of a switch controlling the usual motor and refrigerating apparatus. Obviously this control mechanism may be located either interiorly or exteriorly of the refriga erating space. In common practice the thermostatic unit, which is essentially the bellows and capillary, is anchored by a head or equivalent means, and the movable or opposite end of the bellows is in contact with the switch armor the like, through which movement is transmitted to the switch to exercise proper control of the electric circuit.

The illustrated embodiment of the invention is concerned with an improvement in the therrelationship to the controlling switch or the like, but which does improve the reliability of the unit and permit it to be handled and installed with less likelihood of damage, particularly in connection with the joint between the capillary tubing and the bellows unit.

The invention is particularly concerned with the employment of a bellows normally produced from a drawn cupped shell which is integrally closed at one end as contrasted with a bellows formed from a length of tubing 01' the like open at both ends. With this type of device the bellows indicated generally at I0 is provided with an integral bottom or closed end wall l2. The bellows is normally closed atthe opposite or open end by a relatively thin pressed metal head l4 secured and sealed to the bellows in the orthodox manner by a solder joint IS. The interior of the unit i filled and sealed under a vacuum with a suitable type of thermostatic fluid which forms no part of the present invention, and the nature of which depends on the use to which the unit is to be put.

According to the present invention this unit is anchored and connected at one end to a suitable length of capillary, which may beindicated at l8, of sufiicient length to permit it to extend to the desired refrigerating region, and is provided with a form of support capable of attachment to a stationary wall or support. The opposite or movable end of the bellows, in this case the attached head It, may be provided with a recess 20 either for attachment of an operating stem or for engagement with a stable portion of a switch or valve, as may be desirable.

The integrally formed end wall of the bellows unit illustrated at 12 is centrally pierced and .drifted at 22 to provide an accurately formed tracted length of the bellows unit under the influence of avacuum.

Assembled with the bellows adjacent the head l2 and in contact therewith is a flanged supporting head 30 which, as indicated, may be general ly dome shaped terminating in a circumferential flange or skirt 32 for attachment to a fixed support. The head interiorly at 34 is provided with a generally flat supporting surface for engagemostatic unit which does not affect itsopera'tive ment and contact with the bellows head l2.

in size, and may approximate two to three times Within this flattened area the head is bumped upwardly to provide a circular recess 38 bounded exteriorly of the flat area 34. The bumped up area of the head merges into an upwardly necked portion '38 which may beformed in the domed head by piercing and drifting to provide the neck 38 as a tubular sleeve of reasonably accurate dimensions. The attached length oi. capillary I8 is assembled within the neck 18, which surrounds it with an interior space and fits closely within the inwardly turned neck 24, the insertion of the capillary being limited by a knurl M which predetermines the length of capillary thrust within the sleeve 24. The interior of the space provided by the neck portion of the head 38 and the recess 38 is then tilled with the usual type of soft solder compound indicated at 42, which in one operation and with one union serves to bond the capillary to the neck 24 and the head so, and at the same time the bellows head I: to the supporting head 30. This type of construc-'- tion has been found exceedingly satisfactory both in its economy of manufacture and in the type of joint which is produced.

It will be understood that the accompanyingdrawing for purposes of clarity is much enlarged the actual dimensions of suchia unit.

What is claimed is:

A thermostatic unit comprising a bellows cup closed at opposite end walls, one of said end walls being a plane surface and having a centrally disposed aperture therein, a supporting head forming a ring of contact with the plane surface of said end wall, said ring of contact surrounding and being concentric with said aperture, the portion of said supporting head inside said ring of contact extending inwardly and away from said end walls and terminating in anopening spaced a substantial distance from and larger than said aperture, a capillary tube passing through said opening and extending into said aperture in closely fitted relation thereto, and solder compound surrounding said capillary tube and filling the space formed by said end wall and said inwardly extending portion of said supporting head whereby said supporting head is bonded to said end wall over a substantial area while'said capillary tube is supported relativejto said supporting head and said aperture is sealed around said capillary tube.

. JOHN E. WOODS.

CERTIFICATE or CORRECTION. Patent No. 3,275,506. February 17, 19!;2.

JOHN E. .JWOODS.

It is hereby certified that error appears inthe printed} spec,i1 ication" of the above numbered patent requiringcorrection as follows; Page 2, sec- 0nd column,' line 5, in the claim, after "opposite" insert --ends by"; and that the said Letters Patent should be read with this correction therein Henry Van Arsdale, (Seal) Acting Commissioner OIXPatents 

